Extension battery



FIG. 1 is a rear perspective view of an extension battery, showing our new design;

FIG. 2 is a top plan view of the extension battery shown in FIG. 1;

FIG. 3 is a front elevation view of the extension battery shown in FIG. 1;

FIG. 4 is a right side elevation view of the extension battery shown in FIG. 1;

FIG. 5 is a left side elevation view of the extension battery shown in FIG. 1;

FIG. 6 is a rear elevation view of the extension battery shown in FIG. 1;

FIG. 7 is a bottom plan view of the extension battery shown in FIG. 1; and,

FIG. 8 is a top plan view of the extension battery shown in FIG. 1, where it is illustrated that the extension battery is assembled with an iPhone or any other similar device.

The broken lines showing connectors in FIGS. 1, 2, 4, 6, 7, and 8, recesses in FIGS. 1 and 6, an iPhone in FIG. 8, and a light in FIGS. 1 and 4 are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for an extension battery, as shown and described. 